1. Field of the Invention
This invention relates to telecommunication apparatus adaptable for use in noisy environments including furnace factories, sheet-metal or web production workplaces such as press-working, airplane setup/maintenance works in the airport, print/press factories, and the like, and, more particularly to voice communications apparatus capable of attaining successful transmission of voice messages and phone-calls under high noisy conditions.
2. Description of the Related Art
Conventionally, portable radiotelephones using a sound-shielded headset (sound-insulated transmitter-receiver) are employed as the communication means between workers under noisy conditions full of ambient noises. One exemplary apparatus for such sound-insulated transmitter-receiver is shown in FIG. 11. In this apparatus a plurality of transmitter-receiver 2 (21, 22, . . . , 2n) are operatively coupled over-the-air to one another using radio waves by way of a repeater 1. Any audio messages sent form the repeater 1 may be heard at all of the transmitter-receivers 2 providing simultaneous multidirectional communications. A battery-charge station 3 charges the batteries of respective transmitter-receivers.
Each transmitter-receiver 2 is provided with a headset of excellent sound insulation, which consists of a pad section, a support member and others. This headset is of the headphone type containing therein a microphone, a speaker(s), and a transmitter/receiver function section. Factory workers use such headphones by putting them on their heads to enable simultaneous multidirectional conversations to be carried out attaining required voice communications among them. The microphone detects ear-bone vibrations upon occurrence of a voice message and convert it into a corresponding electrical signal.
In the case where a telephone call is made in noisy environments of relatively higher noise level, it will possibly happen that the microphone also picks up the ambient sounds making it difficult for a worker to hear his or her aimed voice messages due to masking effects of background noises. Under such conditions, it is no longer easy for a worker to accurately transfer his or her voice messages; this necessitates a called party to answer back the caller for confirmation, wasting time and effort with the result in an increase in conversation time while reducing efficiency. One prior known approach for avoiding the problems is to install telephone booths of a sealed environment; another approach is to put each telephone set at a location of relatively low noise levels. Unfortunately, such approaches cannot always offer intended advantages on occasions where there are no such spaces wide enough to permit location of the telephone booth, or on occasions where such ideally low-noise places are not available within the factory. If this is the case, it is a must to put the telephones at noisy locations, which lacks the ability to provide any satisfiable conditions for workers to telecommunicate with each other.
Incidentally, there has been long desired a specific type of telephone handset suitably adaptable for use in voice communications in noisy environments namely, the one that can be directly installed under high noisy conditions and also attain clear conversations without having to be interfered with mixture of background noises with no interruptions in intended telecommunications. On the other hand, in the so-called "sound-insulated" transmitter-receivers for use in working under noisy conditions, successful results are only be achieved by employing workers' case-by-case procedures, which expect a worker who received a telephone call to i) use a selected telephone line being exclusively connected to the repeater, ii) catch the call using a transmitter-receiver that is presently in the out-of-busy state, or iii) ask his or her associate to separately connect with the calle. It will also occur that the called party must put his/her upper body or head into a sound-shielded box within the factory in order to hook up the telephone handset; it may alternatively occur that s/he has to go out of the factory to use one of remotely located telephones in calm areas outside the factory. The prior art sound-insulated transmitter-receivers are unable to insure direct telecommunications with external telephones as linked by way of the public telecommunication networks; accordingly, it will be inevitable for workers to interrupt their own works until completion of the present conversation between the caller and the called party over telephone, or to temporarily change the work to a different kind of one that may be done without the need of attendance of the calling or called worker. In any way, this should result in a decrease in efficiency of workability.
Under high noisy circumstances it is required that, upon occurrence of failures in working machines, such information be rapidly informed to workers so that necessary recovery/repairing procedures can be applied at the earliest convenience. One example is that when a paper quality inspection device (PQD) for inspection of printing machines or a spray dampener (SD) experiences failures accidentally, the resulting printing matter will be expressly lowered in quality causing the productivity to decrease significantly. To eliminate such reduction in productivity, rapid handling for recovery is strictly required at any events.
It is therefore an object of the present invention to provide a communications apparatus capable of retaining reliable communicationability with outside parties in situ under noisy circumstances by letting a repeater have a function of transferring information identical to any external signal inputs toward all of the transmitter-receivers operatively coupled therewith in the apparatus.
It is another object of the invention to provide a voice communications apparatus capable of allowing workers to call over telecommunication channels under noisy in-situ conditions by providing an extra function for enabling interconnectivity between sound-insulated transmitter/receivers and telephone connector devices.
It is yet another object of the invention to provide a voice communications apparatus capable of attaining conversations over public or extension telecommunication lines by entering telephone numbers on part of a telephone operation panel of a telephone connector device to ensure that workers can call a target party under noisy in-situ conditions without having to move far from their original working places during operations.
It is a still another object of the invention to provide voice communications apparatus capable of immediate start of conversations in situ over telephone upon reception of a telephone call while providing as needed the possibility of simultaneous multidirectional transmission/reception of oral messages among a plurality of transmitter-receiver users concerned, to thereby suppress or eliminate degradation of efficiency otherwise occurring when a worker must move far from his or her working place for telephone calls.
It is a further object of the invention to provide a telecommunications apparatus capable of retaining security for covert conversations while preventing leakage of information content to other transmitter-receivers by forcing upon receipt of a telephone call a communication function to be interrupted between the transmitter-receiver of a called party and other transmitter-receivers, and also capable of maintaining mutual communication functions among the other transmitter-receivers to allow these transmitter-receivers to continuously remain active in telecommunications among them thus eliminating any possible interruptions in execution of works required.
It is a yet further object of the invention to provide a telecommunications apparatus capable of allowing telephone responses and call-up of a target party to be smoothly carried out by use of a specific kind of sound and/or visual indication scheme to inform the target person of the presence of a telephone call.